Field of the invention

ABSTRACT

An electric heating device (34) in which is included an electric energy source (45) which is designed as a thin film battery (45). The heating device also includes a resistor heating unit (40) comprising a first material stratum (40) consisting of an electrically conductive polymer material with PTC properties. The resistor heating unit (40) and the electric energy source (45) are disposed adjacent to one another and form a composite unit in which the major surfaces of the first material stratum (40) and thin film battery (45), respectively, face towards one another. Electrodes (42, 43) are connected, by the intermediary of a switch (48), to the poles of the battery (45) and to the resistor heating unit (40).

FIELD OF THE INVENTION

The present invention relates to an electric heating device in whichelectrical resistor heating elements are incorporated with a layer orsubstrate of material.

BACKGROUND AND PRIOR ART

Within many fields of activity, it is desirable to heat different partsof the body, for example for medical purposes or for reasons of comfort.One example is the heating of joints, hands and other parts of the bodyof rheumatism sufferers. Another example is within the areas of sportsand leisure activities where proposals have been put forward for heatedgloves, shoe inlays and other items of clothing as well assleeping-bags.

It is also desirable in the art to devise containers which, on transportor power failure, maintain an elevated temperature in their storagespace. Similarly, there are needs for substrates which, on transport orpower failure, maintain an elevated temperature, for example to avoidthe risk that the temperature falls in accumulators or batteries placedon the substrates--which could lead to a reduction in the quantity ofenergy which can be extracted from them.

To cover these needs numerous solutions have been proposed in the art,these all being based on electric heating with the aid of variousresistor heating elements and electric energy sources, normally dry cellbatteries. As examples of this known technology, mention might be madeof Swedish patent application No. 8402743-2 which describes a gloveintended for rheumatics with inlaid resistor wires and a current sourceso as to develop a thermal effect exceeding 25 W in the glove.

In a corresponding manner, Swedish patent application No. 8404783-6describes a medical undergarment with inlaid resistor heating elementsand a current source in the form of a battery. Electrically heated shoeinlays are described, for instance, in the two German specificationsDE-A-3 904 603 and DE-C-4 000 259. These shoe inlays have inlaidresistor heating elements which are connectable to a battery or othersource of electric energy. In both cases, the resistor heating elementsare in the form of printed conductor paths on a base consisting ofplastic or other non-conductive material. In both cases, the heatingproper is also controlled by means of electric circuit connections so asto as avoid overheating.

As was mentioned above, it is known in the leisure-time sector to makeuse of electrically heated sleeping-bags or garments. One example isdisclosed in US-A-3,443,066 which describes a sleeping-bag or otherclothing garment of flexible, thermally insulating material with inlaidresistor heating wires and batteries for electric power supply.

In automotive engineering, similar ideas have been employed, for exampleto provide heating elements for vehicle seats, an employment whichnecessitates a degree of give in the inlaid resistor heating elements.One example of this technique is described in SE-B-434 204 (7713250-4),in which the give or extensibility has been achieved by making the inlayof meandering loops of resistor heating wires or tapes in a layer in thepadding material of the seat.

Yet a further a example of textile material which can be heatedelectrically is to be found in US-A-4,845,343 in which the resistorwires have been woven into the fabric structure proper.

All of these prior art devices for heating larger or smaller parts ofthe body of a patient or general user suffer from numerous commondrawbacks. One such drawback is that the prior art resistor heatingelements consume considerable quantities of power and are, therefore,expensive in operation. Another drawback is that the possibilities ofregulating the heating effect locally, i.e. within a limited part of thebody are poor--in other words the user must choose between either aheating effect which gives satisfactory heating of the coldest part ofthe body which at the same time results in overheating of other parts ofthe body, or a heating effect which provides comfortable heating of themajor part of the body but insufficient heating within certain otherparts of the body. A further drawback inherent in many of the prior artdevices is that they require separate accumulators whose capacity isoften reduced at low temperatures, since they must be carried atrelatively unprotected positions in the wearer's clothing. Moreover, theseparate accumulators must be carried in some type of belt or the likewhich may prove unwieldy. Another drawback is that some type of externalthermostat is necessary in order to be able to obtain a determinedaverage temperature.

SUMMARY OF THE INVENTION

One object of the present invention is, therefore, to realize anelectric heating device, for example designed as a panel, a laminate, aband, a container etc, in which device one or more of the drawbacksinherent in prior art technology have been obviated. For example, thedevice according to the present invention should be suitable to beincluded in a garment.

A further object of the present invention is to realize a device, anarrangement or an article, for example a garment of clothing, of adesign which entails that the heating effect varies locally in responseto the local heating requirement.

Yet a further object of the present invention is to render the heatingdevice so thin and flexible that it can be inlaid between two textilelayers in a garment of clothing or the like without the appearence orother properties thereof being appreciably altered. Still a furtherobject of the present invention is to devise automatic regulation of theaverage temperature without the need of an external thermostat. Yet afurther object of the present invention is to realize a heating devicewhich includes an electric power source which cooperates with a heatingelement included in the heating device so as to avoid or counteract theeventuality that the available portion of the capacity of the powersource is reduced as a result of cooling of the energy source and,instead, even to increase the available capacity of the energy source inthat heat generated in the immediate proximity of the energy sourceraises the temperature of the energy source. Still a further object ofthe present invention is to realize reflection of heat towards theenergy source by particular placing of the energy source.

These and other objects of the present invention will be attained if theheating device is constituted as a thin film battery formed as acomposite unit with resistor heating means combined with a substratelayer of material.

The heating element according to the invention consists of a polymermaterial with so-called PTC properties (Positive TemperatureCoefficient), in particular an electrically conducted thermoplasticmaterial such as conductive, butyl inoculated polyethylene.

The thin film accumulator may advantageously be of the lithium type andhave a number of mutually stratified layers including a lithium layer, apolymer electrolyte layer, a vanadinoxide composite layer and aconductor layer.

Electrode material most suitably consisting of a conductor material isunited with the heating element by casting, screen printing, gluing withelectrically conductive glue or vacuum coating in a suitable pattern soas to make possible electric connection to the thin film battery.

A control circuit may be provided as a conductive path with a connectedswitch between the two poles of the battery, but is preferably a controlcircuit with circuit elements for sensing and controlling the batteryand possibly also limiting activation time.

The expression "garment" is here taken to signify not only clothinggarments such as gloves, waistcoats and the like, but also shoe inlays,sleeping-bags or seat heaters or cushions, for example for leisure timeactivity purposes.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention will now be described in greater detailhereinbelow, with particular reference to the accompanying drawingswhich show embodiments of the present invention. In the accompanyingdrawings:

FIG. 1 shows a section through one embodiment of an assembly for use ina heating device according to the present invention;

FIG. 2 shows an example of a garment which is designed according to thepresent invention;

FIG. 3 schematically illustrates a preferred thin film accumulator foruse in the present invention;

FIGS. 4a-d show four examples of different methods of uniting electrodematerial and heating foil material;

FIG. 5 schematically illustrates a first example of how the heating foilmaterial and thin film accumulator may be united;

FIGS. 6a,b schematically illustrate a second example of how the heatingfoil material and thin film accumulator may be united;

FIGS. 7a,b schematically illustrate a third example of how heating foilmaterial and thin film accumulator may be united;

FIGS. 8-9 schematically illustrate further examples of heating unitswhich may be used in practical application of the present invention; and

FIGS. 10a-d schematically illustrate examples of heating units providedwith a heat reflecting layer.

FIG. 1 schematically shows a section through one embodiment of thematerial (an aggregate consisting of several strata) 33 for use in anelectric heating device 34 (cf. FIGS. 2 and 9) according to the presentinvention as described hereinbelow, for example in a garment, acontainer, an underlay blanket for accident victims, and so on. Theaggregate is formed from, or contains, at least a first stratum 1 whichconsists of or includes at least one layer of an electrically conductivepolymer with PTC properties. The first stratum 1 is disposed adjacentand, as a rule, connected to a second stratum 2 included in theaggregate and consisting of a thin film battery 5 thin film accumulator5. As is apparent from the embodiment illustrated in FIG. 1, theaggregate generally includes protective layers 3 disposed on either sideof the two strata 1, 2 and consisting, for example, of plastic material,metal such as metal foil or textile material, or of a combination of twoor more of these materials. The structure of the first, second and thirdstrata 1,2 and 3 will be described in greater detail hereinbelow.

FIG. 2 shows one example of an application of the present invention inwhich the device 34 is designed as a heating glove 4 for, for example,rheumatics.

FIG. 3 shows an example of a thin film battery 5 of a type which isadvantageously employed in the practical application of the presentinvention. In the illustrated embodiment of the thin film battery 5,there is included a lithium layer 6 acting as negative pole, a subjacentpolymer composite layer 7 acting as electrolyte, a composite layer 8acting as positive pole and an electric conductor 9 connected to thecomposite layer 8. Such a thin film battery is not much thicker thannormal letter paper, approx. 0.2 mm. The composite layer 8 consists of amixture of the electrolyte and a compound which readily entraps lithiumions e.g. vanadium oxide). The lithium ions pass through the electrolyteto the composite layer 8 (the positive pole), while the electrons takethe outer path from the lithium layer 6 (the negative pole) to thecomposite layer 8, i.e. go via an outer load (not shown) and theelectric conductor 9. The load constitutes a resistor heating unit andwill be described hereinbelow. Both the ions and the electrons arestored in the composite layer 8 and pass back to the lithium layer 6when the battery is recharged.

Thin film batteries of this type may be purchased from variouscommercial sources, e.g. the Japanese firm Yuasa Battery, the Canadianfirm Hydro Quebec and the Japanese firm Sharp Corporation. Examples ofliterature in which this type of thin film battery is described is thebook published by Elsevier Science Publishers B.V. in 1991 entitled"Chemistry and Energy-I", C. A. C. Segueira (editor) which includes onpp. 153-162, an article written by Jorgen S. Lundsgaard et al "TheAll-Solid-State Lithium Polymer Electrolyte Battery", and on pp. 163-175includes an article written by M. A. G. Martins et al "All-Solid-StateThin-Film Polymer Electrolyte Batteries". Another example is Koksbang etal, "Rechargeability and Rate Capability of Polymer ElectrolyteBatteries at Room Temperature", Journal of Power Sources, 32 (1990) pp.175-185.

According to the present invention, the aggregate includes a heatingunit in which is included a polymer material with PTC properties. Onesuch particularly suitable material may be obtained from Neste PolymerCompounds AB, Sweden under the designation ET-Semicon CT 6422:70 or6002:70. These materials are semiconductor thermoplastic materials.Another material which has been utilized in practical tests and whichhas been obtained from Norells Sweden AB is ET-Semicon CT 8711:70. Forconnecting these electrically conductive polymer materials 10 with PTCproperties, use is made of, for example, cast electrodes (FIG. 4a) anelectrode material screen-printed on the polymer layer (FIG. 4b), anelectrode material applied to the polymer layer by a vacuum coatingmethod (FIG. 4c), or a partly cast electrode material in the form of alattice (FIG. 4d). It will be obvious to a person skilled in the artthat other connection techniques are also applicable within theframework of the present invention. The lattice-formed electricallyconductive electrode material in FIG. 4d is, for example, cast onopposing sides of the polymer layer or connected to the polymer layer bygluing. In FIGS. 4a-d, the polymer layer has been given referencenumeral 10 and the electrode material reference numeral 11. In theembodiments illustrated in FIGS. 4b and 4c, the electrode material is,in certain practical applications, connected to the polymer material 10by a welding process.

A thin film battery of the type which is preferred in the presentinvention has preferably an average voltage of 2.4 V/polymer layer. Inorder to obtain a sufficiently high voltage, a number of layers (cf.FIGS. 5-7) are generally laminated. In one expedient embodiment of thepresent invention, use is made, for example, of ten laminated layers ofbatteries, in which event a polar voltage of 24 V is obtained. Vacuumtechnique is employed in one preferred production technology forlaminating the various thin film batteries. The different layers areplaced on one another, a series connection of the different batteriesbeing obtained in that the positive and negative poles of adjacentbatteries are connected to one another, whereafter the layer ofbatteries is compressed and vacuum sealed. The sealing materialconsists, in one preferred embodiment, of an aluminum foil whose insideis coated with a layer of an electrically insulating material, forexample polyethylene based hot-melt glue.

FIG. 5 schematically illustrates one embodiment of the present inventionin which a thin film battery 12 consisting of a plurality of strata isformed from ten mutually superposed and interconnected thin filmbatteries 5. The composite thin film battery 12 is connected by means ofa conductor 13 to one current distributor 11 in the electricallyconductive polymer material layer 10. The negative pole of the compositethin film battery 12 is connected by means of a conductor 14 to acharger terminal 15 which, via a switch 17 and a conductor 18, isconnected to a second current distributor 11' in the electricallyconductive polymer layer 10. Both of the current distributors 11 and 11'are located a distance from one another which is determined by theelectric and thermal properties of the polymer layer and by the thermaleffect which is to be emitted by the polymer disposed between thecurrent distributors. The current distributors 11,11' and the polymerlayer 10 constitute the heating unit 19 of the device.

The charging terminal 15 is, via a conductor 16, connected to the onecurrent distributor 11. When a charger is connected to the chargingterminal 15, the positive and negative poles of the device are therebycoupled to corresponding poles in the thin film battery 12 consisting ofa plurality of layers.

The electrically conductive polymer layer 10 is, for example, made ofET-Semicon having the commercial designation CT 6002:17. The twoelectrodes or current distributors 11,11', consist, for example, ofwire-like electric conductors which are cast in the polymer layer or areformed from a metal foil or alternatively synthetic metal foil, e.g. ICPmaterial (Intrinsically Conductive Polymers). The wire-formed conductorshave, in one preferred embodiment, a diameter of 0.9 mm and metal foilthickness of 25 um. The battery 12 consisting of a plurality of stratais cast in or sealed against the surroundings by an electricallyinsulating, water resistant and water impermeable material inapplications in which the thin film batteries 5 are sensitive tomoisture. The polymer material layer 10 needs no correspondingprotection. In this embodiment in which the heating layer 10 and thethin film accumulator 12 are discrete from one another, the advantagewill be afforded that the accumulator can be replaced. In that theelectric connections 13,14,16,18 between the battery and the heatingunit are conductive, body movements on the part of the wearer will befacilitated.

One major advantage in the employment of an electrically conductivematerial of the PTC type is that the heating effect can be locallyregulated, i.e. colder positions emit more heat than warmer positions.This regulation is automatic as a result of the PTC properties of thematerial.

FIGS. 6a and 6b show yet a further embodiment. In this case, theelectrically conductive polymer layer 20 with PTC properties included inthe heating unit 19 by screen printing has been provided with a firstbatch of electrodes 21 and a second batch of electrodes 22. The twoelectrode batches are disposed such that the electrodes are in spacedrelationship from one another. The first batch of electrodes 21 has aprojecting contact element 23 and the second batch of electrodes 22 hasa projecting contact element 24. The heating unit 19 is glued with anelectrically insulating glue against the positive pole layer 25 of athin film battery 26 composed of a plurality of thin film batteries 5.As electrically insulating glue for this purpose, use may be made ofABLEBOND 958-11 from Sikema AB. For connecting and disconnecting theunit, there is a switch 27 which, with conductors 28,29, is connected tothe terminal 23 and negative connection 30, respectively, of thecomposite thin film battery 26. The positive connection 25 is, by theintermediary of a contact element 35 projecting from the battery 26,electrically connected to the contact element 24 of the second batch.For recharging, there is a recharge terminal 31 with associatedconductors 32,38.

As an alternative to the electrically insulating glue employed in FIGS.6a and 6b use is made, in certain applications, of a generally thinelectrically insulating film of plastic material, for examplepolyethylene or the like, which is fixed, e.g. fused to the surface ofthe electrically conductive polymer layer 20 turned to face towards theheating unit 19. As a rule, the film of plastic material covers theentire major surface of the polymer layer 20. In the embodiments inwhich the composite battery 26 needs protection against moisture (watervapor or water) the film fixed to the heating unit 19 is generallybonded (e.g. welded or glued) with the protective material whichsurrounds other parts of the composite battery 26. Hereby, the polymerportion forms a part of the protective sealing of the battery, at thesame time as the thermal generation of the polymer increases the usableproportion of the energy power content of the battery. In addition, thisembodiment makes it possible for the thermal generating portion of theheating device to be placed in the immediate vicinity of that body orthat space which is to be heated.

A major advantage inherent in this embodiment is that the aggregate 33formed from the heating unit 19 and the thin film battery 26 is suitablefor mass production in running series for later cutting into units.After the cutting operation, the cut part is generally enclosed in anelectrically insulating casing which also protects against water andwater vapour.

FIGS. 7a and 7b show yet a further embodiment of a heating device 34 inwhich is included the heating unit 19 formed by the electricallyconductive polymer layer 40 and a number of mutually adjacent thin filmbatteries 5 forming a composite thin film battery 45. In this case, thecurrent is passed through the polymer layer 40 substantially parallelwith the two defining surfaces 54,55 of the polymer layer from the firstdefining surface 54 to the second defining surface 55 of the polymerlayer 40. This is achieved in that one or more electrode bands 41 and43, respectively, abut against the first defining surface 54 and seconddefining surface 55, respectively, of the polymer layer 40. When morethan one electrode band 41,43 abuts against any of the defining surfaces54,55, the electrode bands are, as a rule, separated at each suchsurface by electrically insulating layers 42,44 which extend betweenmutually adjacent electrodes. The surfaces 54,55 of the polymer layer 40are thereby electrically insulated between the electrode bands 41,43.The insulating layers 42 and 44 are provided so as to prevent electronmigration transversly through the polymer down to the conductive layerof the composite thin film battery 45. Instead, the sought-for morehorizontally directed current will be obtained through the polymer,which gives uniform heat.

The thin film battery pack 45 has its positive pole 46 combined with thepolymer layer 40 so that electric contact exists between the electrodeband or electrode bands 41, respectively, and the positive pole layer 46at the battery pack. The positive pole layer 46 is provided with aprojecting contact strip 47. As will be apparent from FIG. 7b theelectrode band or the electrode bands 43, respectively, are, via aswitch 48, connected to the negative pole 49 of the thin film battery45. In order to make possible recharge, there is disposed a rechargeterminal 50 which, with conductors 51,52 is connected to the negativepole 49 and the contact plate 47, respectively, projecting from thepositive pole 46.

As material for the polymer layer 40, use is advantageously made in thisembodiment of an electrically conductive plastic ET-Semicon with thetype designation CT 6422:70 or CT 6002:70. Application of the electrodebands 41,43 is, for example, effected using a technique corresponding tothat described in the foregoing, for example by screen printing, gluingor vacuum coating. In order to electrically connect the individuallyelectrode bands 43 to one another, preferably the entire outside of theresistor unit 40 is covered with a generally thin electrode layer 53.Also the whole of the inside of the polymer material 40 is, in certainembodiments, coated with thin electrically conductive material.

In certain practical applications, in the embodiment illustrated inFIGS. 7a and 7b, a generally thin electrically insulating film ofplastic material, for example polyethylene or the like, is fixed, forexample fused to the surface of the electrically conductive polymerlayer 40 facing towards the heating unit 19, while in other embodiments,such film is absent. As a rule, the film of plastic material covers theentire major surface of the polymer layer 40, in which event thepositive pole of the battery is electrically connected to the electrodes41 by a separate lead wiring (not shown in the figures). In thoseembodiments in which the composite battery 45 needs protection againstmoisture (water vapor or water) and in which the film occurs, the filmbonded to the heating unit 19 is generally joined (e.g. welded or glued)to the protective material which surrounds other parts of the compositebattery 45. In embodiments in which the film is absent, moistureprotection is obtained in that the casing or housing surrounds both theheating unit 19 and the battery (cf. also FIG. 9 below). Where the filmis absent, the above-mentioned lead wiring to the positive pole of thebattery is not required. In both of the embodiments, the heat generationof the polymer increases the extractable proportion of the energy powercontent of the battery. Moreover, this embodiment makes it possible forthe heat generating portion of the heating device to be placed in theimmediate proximity of that body or that space which is to be heated.

Also in embodiments described in the preceding paragraphs, the aggregate33 formed by the heating unit 19 and the thin film battery 45 issuitable for mass production on a production line for later cutting intounits, in particular in the embodiment in which the insulating plasticlayer between the resistor unit and the battery is not employed.

FIGS. 8-9 illustrate various conceivable embodiments and placements ofthe resistor heating unit 60, the thin film battery 61 and the operatingunit 62.

FIG. 8 shows one embodiment in which the polymer layer 60 of theresistor heating unit 19 and the thin film battery 61 are physicallyinterconnected with one another and, in one preferred version, areincluded in a laminate. The operating unit 62 is disposed at a separateposition and electrically connected by the intermediary of conductors28,29 with the polymer layer 60 and the negative pole 30 of the thinfilm battery 61, respectively, of the composite unit in which theresistor unit 19 and the thin film battery 61 are included.

In the embodiment illustrated in FIG. 8, an electrically insulating andwater-impermeable plastic material layer 67, e.g. a polythene layer, isdisposed between the electrically conductive polymer layer 60 of theheating unit 19 and the battery 61 in order to provide a particularlygood moisture seal about the battery 61. This plastic material layer 67is fused with the water and water vapor-impermeable casing 64 whichsurrounds the remaining portions of the composite battery 61. Thisdesign corresponds to the design in FIGS. 6a and 6b, but with thedifference that the plastic material layer 67 has been applied onto thepole layers 25, before the electrically conductive polymer layer (orresistor layer) 20 with its conductors 21,22 has been mounted in place.As will be apparent from FIG. 8, the contact element 24 is connected tothe positive pole layer 25. Furthermore, the negative pole connection 30is, via the insulating conductor 29, electrically connected to theoperating unit 62 which is also electrically connected to the secondconnection of the heating unit 19 and, thereby, the contact element 24via the conductor 28. This version may advantageously be employed wherethe requirement on mobility is less severe, for example in sole inlays.

FIG. 9 illustrates yet a further embodiment in which the pole layer 65of the thin film battery 61 is in directly conductive contact with anelectrode material layer 66 connected to the electrically conductivepolymer layer 60 of the heating unit 19. This combination of thin filmbattery 61 and heating unit 69 forms, for example, a laminate and isillustrated, in this drawing Figure, enclosed in a moisture-proof andwaterproof casing 64. The operating unit 62 is, in FIG. 9, shown asdisposed outside the casing 64 and connected with the heating elementvia the conductors 63.

FIGS. 10a-c show schematic partial sections of combinations of theheating element 1 and thin film batteries 2 designed in accordance withthat described in the foregoing. The letter A is taken to signifythermal energy which is in motion in a direction from the heatingelement 1 and towards a body or a space which is to be heated. In all ofFIGS. 10a-c, the heating element 1 is disposed between the thin filmbattery 2 and the above-mentioned body or space. The combinationsillustrated in the figures also include a casing 64 whose one wall 64ais located on that side of the thin film battery 2 which is turned toface away from the body or the space which is to be heated. The otherwall 64b of the casing is located on the opposite side of the thin filmbattery 2. Both of the walls are closely united with one another bymeans of a closure 70 in the edge region of the thin film battery 2.Both of the walls of 64a,b of the casing are substantially parallel withthe major surfaces 36,37 of the thin film battery.

In FIGS. 10a-c the heating element 1, the thin film battery 2 and bothwalls 64a,b of the casing are shown as disposed in spaced relationship.In certain practical applications, spacer elements (not shown in thefigures) are provided for maintaining these spacings, in particularembodiments in which the device is to form a mechanically rigid unit. Inother embodiments, for example when the device is included in a garment,the heating element 1, the thin film battery 2 and the walls 64a,b aremoveable towards and away from one another while being fixed in relationto one another at regular distances. FIG. 10d shows a partialmagnification of the marked region in FIG. 10a. It will be apparent fromthe partial magnification that the wall 64a of the casing is, in theillustrated embodiment, composed of a metal foil 68 consisting of one ormore layers and a plastic layer 69 on either side of the metal foil. Themetal foil is preferably coated with the plastic layers.

FIGS. 10a and 10b show embodiments in which the casing 64 in FIG. 10asurrounds only the thin film battery 2 and in which the casing 64 inFIG. 10b surrounds both the thin film battery 2 and the heating element1.

FIG. 10c shows one embodiment in which a layer 71 of electricallyinsulating material which, in addition, is impermeable to both moistureand water, is disposed between the heating element 1 and the thin filmbattery 2. In addition, the material in the layer 71 is of poor thermalinsulation or otherwise expressed, good thermal permeability. The wall64 of the casing is sealingly connected with the layer.

On use of the embodiments described in FIGS. 10a-d, the thermal energyis reflected by the metal foil 68 back towards the battery 2, wherebythis receives elevated temperature which, in turn, makes it possible fora greater portion of the energy power content of the battery to beavailable to be converted into thermal energy in the heating element 1.

In the description of FIGS. 10a-d, use has been made of the generalexpressions heating element 1 and thin film battery 2. This is herebytaken to signify that the element 1,10,20,40,60 and/or the battery2,12,26,45,61 as required is disposed in accordance with one of thealternatives described in the foregoing.

When the above-described embodiments of thin film battery 2,5,12,26,45,61 and the heating unit 19 which, as a rule, include anelectrically insulating polymer material located between the thin filmbattery and the heating unit, are to be produced in the form of longbands, the advantage will be attained that the band constitutes anintermediate product from which is separated portions or part lengthsadapted to the requirements of the pertinent practical application.However, it is obvious that not only the length of the separated part isadaptable to the relevant practical application, but also the form ofthat part which is cut off.

The size of the separated part or the separated portion is adapted inaccordance with the power/energy need which the particular applicationrequires. The construction of the present invention entails that it ispossible beforehand to determine the desired generated output persurface unit by dimensioning the battery for a given pole voltage(number of partial batteries 5), selecting polymer material with acertain volume resistivity and/or selecting a certain electrode spacing.The layer thickness of the polymer material is also determinative of thepower output per surface unit, There will hereby be obtained apredetermined operational time of that device in which the separatedpart is included, irrespective of the surface area of the separatedpart. As a rule, the band is provided with a contact plate for electriccontact between heating unit, thin film battery and operating unit, inwhich event the contact plates abut against the positive or negativepoles of the thin film battery, The separated part is thereby simplyinterconnectable with an operating unit 27,48,62, e.g. as describedabove with particular reference to FIG. 9. After the cutting operation,the cut portion is generally enclosed in an electrically insulatingcasing which is also water and water vapour proof. Requisite conductorsfor, for example, the operating unit and battery charger are sealinglylead through the casing.

In the foregoing description, it is disclosed that the aggregate 33(material) includes a number of strata which are disposed adjacent oneanother. The expression "disposed adjacent one another" encompasses amultiplicity of embodiments, for example that the strata arecontinuously interconnected, that they are discontinuouslyinterconnected, that they are laminated, that they are loosely disposedin relation to one another in portions which are followed by sectionswhere they are interconnected with one another, that they are onlyinterconnected with one another at points, that only two layers out ofthree are interconnected with one another within a given area, that thelayers are interconnected with one another in but the edge regions of,for example, a band, that the strata are laid with the major surfacesfacing one another about, for example, a body and are kept in place byouter fixing devices, that the strata are compressed in that asurrounding protective casing is wholly or partly evacuated of its gascontent, etc.

In the above description, the term thin film battery has been employed.This is taken to signify both rechargeable thin film batteries andnon-rechargeable batteries (primary batteries). The type of battery isadapted to suit the particular practical application in which thepresent invention is employed.

The description and the accompanying drawings show specific orientationsof the poles of the thin film batteries. It will be obvious to theskilled reader of the specification that the disclosed orientationsmerely constitute examples of embodiments and that the thin filmbatteries in other embodiments have reverse orientation, entailing thatthe positive and negative poles have changed place.

It will be obvious to the skilled reader that, even if embodiments havebeen described in the foregoing in which the resistor heating unit 19consists solely of an electrically conductive polymer layer1,10,20,40,60, the heating unit 19 is provided, in other embodiments,with more than one electrically conductive polymer layer.

In certain practical applications of the present invention, the deviceis designed so as to constitute a rigid and mechanically stable unit,for example be designed as a container. In other practical applications,the device is designed so as to form a flexible and bendable unit.Depending upon those requirements placed by the relevant practicalapplication, the device includes material which entails that the thusformed aggregate 33 is bendable, extendable, elastic, resilientlyyieldable, mechanically stable etc.

In the above description, use has occasionally been made of suchdesignations as upper, lower, right, left etc. These designations havebeen employed solely to facilitate presentation of the invention. Itwill be obvious to a person skilled in the art that the describedtechnique generally permits any optional orientation in space.

The above-detailed description has referred to but a limited number ofembodiments of the present invention, but it will be readily perceivedby a person skilled in the art that the present invention encompasses alarge number of embodiments without departing from the spirit and scopeof the appended claims.

We claim:
 1. An electric heating device comprising an electric energysource, a resistor heating unit comprising a first material stratumcomprising portions of electrically conductive polymer material with PTCproperties, said first material stratum having a pair of mutuallyoppositely arranged major surfaces, in which the polymer material withPTC properties is united with electrode material which electricallyconnects said electrically conductive polymer material to the energysource, and a regulator unit for regulating current supply to theresistor heating unit, wherein the electric energy source comprises athin film battery also having a pair of mutually oppositely arrangedmajor surfaces, and wherein said first material stratum is physicallyconnected to said thin film battery such that the energy source and theresistor heating unit form a composed unit in which respectively oneeach of the major surfaces of said battery and of said first materialstratum are turned to face towards one another.
 2. The heating device asclaimed in claim 1, wherein one pole layer of the thin film battery isin direct contact with the electrode material applied to the one majorsurface of the electrically conductive polymer material of the firstmaterial stratum.
 3. The heating device as claimed in claim 1,comprising an electrically insulating material layer disposed betweenone pole layer of the thin film battery and the adjacent major surfaceof the polymer material of the first material stratum.
 4. The heatingdevice as claimed in claim 1, wherein in said composed unit, at leastthe thin film battery is moisture sealed in relation to the surroundingsof the battery.
 5. The heating device as claimed in claim 4, wherein thefirst stratum and the thin film battery are tightly enclosed in a commoncasing which is impermeable to water and water vapor.
 6. The heatingdevice as claimed in claim, 1, wherein the electrically conductivepolymer with PTC properties is at least one of:a plastic in which anelectrically conductive filler is distributed as an electricallyresistive network and which, on heating, has the property of expandingunder progressive reduction of electric current paths through theelectrically resistive network and vice versa, until a stage ofself-regulated thermal stability is achieved; and a butyl-inoculatedpolyethylene plastic which has been rendered electrically conductive byadmixture of carbon black.
 7. The heating device as claimed in claim 1,wherein the electrically conductive polymer has said electrode materialcombined therewith by casting, gluing screen pressing or vacuum coating.8. The heating device as claimed in claim 1, wherein the electrodematerial consists at least partly of at least one of metallic materialor synthetic metal material.
 9. The heating device as claimed in claim1, wherein there is provided, in regions where the first materialstratum and the thin film battery form said composed unit, a materiallayer which reflects thermal energy incoming towards the stratum; saidbattery being disposed between said material layer reflecting thermalenergy and one of: a body; and a space which is heated by the device.10. The heating device as claimed in claim 1, wherein the electricenergy source and the resistor heating unit are enclosed in a textilematerial.
 11. The heating device of claim 1, wherein said electrodematerial comprises a first batch of electrodes and a second batch ofelectrodes, said first and second batches of electrodes both beingprovided at the major surface of said first material stratum facing saidthin film battery, said first batch of electrodes being electricallyconnected to a first pole of said thin film battery arranged at themajor surface of said thin film battery facing said material stratum,said second batch of electrodes being electrically connected to a secondpole of said thin film battery.
 12. The heating device of claim 11,wherein said first material stratum comprises a pair of projectingcontact elements each of which is electrically connected respectivelywith said first and second batches of electrodes, and wherein said thinfilm battery comprises a projecting contact element electricallyconnected with the projecting contact element of said first materialstratum which is electrically connected with said first batch ofelectrodes.
 13. The heating device of claim 1, further comprising anelectrically insulating layer disposed between the mutually facing majorsurfaces of said battery and of said first material stratum.
 14. Theheating device of claim 1, wherein said electrode material comprises afirst batch of electrodes provided at the major surface of said firstmaterial stratum facing said thin film battery and a second batch ofelectrodes provided at the major surface of said material stratum facingaway from said thin film battery, said first batch of electrodes beingelectrically connected to a first pole of said thin film batteryarranged at the major surface of said thin film battery facing saidmaterial stratum, said second batch of electrodes being electricallyconnected to a second pole of said thin film battery.
 15. The heatingdevice of claim 14, further comprising electrically insulating layersprovided at both major surfaces of said first material stratum disposedbetween said first and second batches of electrodes.
 16. The heatingdevice of claim 15, wherein substantially the entire outside of saidfirst material stratum at the major surface thereof facing away fromsaid thin film battery is covered with an electrode layer electricallyconnecting said second batch of electrodes.
 17. The heating device ofclaim 15, wherein substantially the entire inside of said first materialstratum at the major surface thereof facing towards said thin filmbattery is covered with an electrode layer electrically connecting saidfirst batch of electrodes.
 18. The heating device of claim 15, whereinsubstantially the entire outside of said first material stratum at themajor surface thereof facing away from said thin film battery is coveredwith an electrode layer electrically connecting said second batch ofelectrodes, and substantially the entire inside of said first materialstratum at the major surface thereof facing towards said thin filmbattery is covered with an electrode layer electrically connecting saidfirst batch of electrodes.